These are the words Deputy District Attorney Amanda Zambor used to describe Daniel Marsh during opening statements on Tuesday.

"As evidence unfolds, you will see this is a deadly and dangerous combination, which led to the torture of Oliver 'Chip' Northup and Claudia Maupin," Zambor told the eight-woman, four-man jury.

Marsh, 17, rested his head on his interlaced fingers, closing his eyes as Zambor continued to describe the night of April 14, 2013, when Northup, 87, and his wife Maupin, 76, were found stabbed to death inside their Davis condominium.

Marsh is charged with both murders, as well as enhancements for lying in wait and torture, according to court documents. He pleaded not guilty by reason of insanity on June 2, allowing a continuance of the long-awaited trial. Though Marsh was 15 at the time, he is being tried as an adult.

With a photograph of the couple projected on the screen behind her, Zambor continued to paint a picture of a 15-year-old boy who was "creeping around" the Davis streets, looking for someone to kill.

According to Zambor, Marsh has had "thoughts of killing people since he was 10 years old," and when he found his mother's six-inch hunting knife, he "thought to himself the time is now."

After approaching more than 40 homes that night, checking for open doors and windows, Marsh settled on the Northup residence, located on the 4000 block of Cowell Boulevard in Davis. He broke into the home by cutting the screen in an open window at the back of the house, climbing in and standing above the sleeping couple before thrusting the buck knife into Maupin, whose "pleas fell on deaf ears," Zambor said.

Marsh remained unmoved as Zambor played a videotaped interview, in which he described the details of the murder.

"It was finally happening," Marsh said in the recording. "It was like an out-of-body experience. It didn't feel like I was there, that it was real."

On the video, Marsh continued to answer the officers' questions, letting out an occasional chuckle when describing how he started stabbing Maupin and "she wouldn't die." When Northup awoke, Marsh quickly stabbed him in the neck, subduing the 87-year-old man.

"I stabbed her a lot," Marsh said. "It took a long time."

The Yolo County Coroner's Office reported that Maupin had 67 stab wounds, while Northup had 61.

The video continued to play while many friends and family of the Davis couple began to weep in the audience.

"I made sure they were both dead, and I kept stabbing their dead bodies," Marsh said in the recording. "I don't know why, it just felt right."

Marsh told officers he went to the kitchen, retrieving a cellphone and a drinking cup to place inside each of the victims.

"I just wanted to f--- with the people, the investigators," he said. "It felt amazing, it felt great. It was pure happiness, adrenaline, dopamine rushing over me."

When the video stopped, Public Defender Ron Johnson delivered his opening statement, asking the jurors not to focus on what happened, but why.

Johnson spoke to his client's mental state and history of depression, anorexia, and years of therapy to cope with these conditions.

Marsh's depression started when he was 11 years old, and resurfaced again two years later, where he was prescribed Prozac, an antidepressant, for the first time.

"This was the beginning of what was to become a very dark, difficult path for Daniel," Johnson said, noting the neglected side effects of Marsh's medication throughout the years "transformed him from a young boy into a reclusive person who withdrew completely from society."

The long, untreated side effects from the changing medications contributed to morbid thoughts about death and violence, Johnson said.

Marsh told numerous therapists about his thoughts of suicide and violence towards others, and they chose to continue or change his medications, even when an eating disorder emerged.

"He nearly starved himself to death," Johnson said. "The thoughts of violence continued to worsen, and not once did they take him off the drugs."

In early 2013, Marsh had an argument with a friend and "had to do everything he could to keep himself from killing his friend," Johnson said.

With opening statements finished, Northup's longtime friend and bandmate Wayne Ginsberg took the stand, illuminating what happened the day of the murder.

Ginsberg and Northup played together in the Putah Creek Crawdads, a local folk band, for many years. The day following the incident, the band had two engagements, neither of which lead singer Northup attended.

Ginsberg grew concerned, calling four different phone numbers for the couple, leaving numerous messages. He found it "extremely unusual" for Northup not to answer or call him back.

The band played at Mojo's Lounge and Bar that night, without Northup, where Ginsberg asked Maupin's daughter Laura Ortiz about her stepfather's whereabouts.

Growing concerned herself, Ortiz left Mojo's, driving straight to Davis with her boyfriend at the time, Joaquin Feliciano. The couple knocked on Northup's door, calling out his name, but the "house was put to sleep," Feliciano said during his testimony.

Walking to the back of the residence, Feliciano found a window where the screen was cut, creating a "flap" to enter the residence, prompting the couple to call the police.

At about 9:30 p.m., Sgt. Doug Bates with the Davis Police Department arrived, telling the couple to wait in their car down the street while three other officers arrived moments later. Another officer shined his flashlight into Northup's bedroom, giving him the first glimpse of the mutilated couple.

Forcing entry into the home, Bates and another officer cleared the house room-by-room before entering the far bedroom, discovering their bodies.

Marsh's defense attorney Johnson declined to cross-examine most of the witnesses Tuesday.